The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Passive components for use in an acoustic transducer are manufactured by adding metal oxide filler to unprocessed epoxy resins.
In the process of making the passive components as illustrated in FIG. 1, the epoxy resins, a hardener, and the filler are measured and mixed well by hands first and then with a machine to a sufficient degree.
Then, the mixture is casted after first removing gas generated while mixing the epoxy resin, hardener, and filler followed by a secondary removal of gas, curing, cutting out and finishing casted passive components into final passive component products.
It is important in this process of manufacturing the passive components to have a proper dispersion of the metal oxide filler added to the unprocessed epoxy resins. An improper or incomplete dispersion causes agglomeration in powders of the epoxy resin having the metal oxide filler added, and thus causes failure in the uniformity of the resultant passive components.
Possible causes of the powder agglomeration include tendency of the powder particles to reach a stable state from relatively high surface energy over their surfaces through mutual aggregation; inter-particle Van der Waals force stronger than the particle's own gravity; or other causes such as hydrogen bonding on the surface, moisture absorption and chemical bonding, etc.
Storing the material in a desiccator capable of adjusting humidity may help to avoid the adsorption by moisture to some extent, since a complete prevention of the aggregation of material in the dry state is difficult to achieve.
There is, however, still difficulty of completely preventing the inter-particle aggregation of the powders even by such method of storing the material in the desiccator, and as well as a hassle to keep the powders in the desiccator.